BGN2/bgn2/src/Fp.hpp

#ifndef __FP_HPP
#define __FP_HPP

#include <ostream>
#include <sstream>
#include <random>

#include "mydouble.h"
extern "C" {
#include "fpe.h"
#include "scalar.h"
}

class Fp
{
    // Necessary for private and public keys to have access to private members
    friend class PrivateKey;
    friend class PublicKey;

    public:
        Fp();
        Fp(const fpe_t& input);
        Fp(int input);

        void set(const fpe_t& input);
        void set(int input);
        void set_random();

        Fp operator-() const;
        Fp operator+(const Fp& b) const;
        Fp operator-(const Fp& b) const;
        Fp operator*(const Fp& b) const;
        Fp operator/(const Fp& b) const;

        bool operator==(const Fp& b) const;
        bool operator!=(const Fp & b) const;
        bool Fp::is_zero() const;
        
        // Problem: thanks to the magic of weird typedefs, scalar_t is actually an array, which complicates returning it
        // Solution: make the return value a reference
        const scalar_t& to_scalar() const;
        
        friend std::ostream& operator<<(std::ostream& os, const Fp& output);
    
    private:
        unsigned long long Fp::mpz2ull(const mpz_class& n) const;
        fpe_t element;
        scalar_t scalar;
        bool no_change;
};

#endif